Given a suitable MTM crossover design...what would be the outcome of eliminating the box yet keeping the same XO.....minus the addition of a highpass filter of course and the addition of a powered bass unit. I would imagine the baffle dimensions would have to be adjusted if this is at all possible in the first place. The Midwoofers in question have a QTS of .56 if that matters.
mayhem13 said:
You would rapidly lose bass response below the dipole cut off frequency for you baffle dimension.
mayhem13 said:
Most likely, the MTM crossover was designed for the particular baffle dimension...
mayhem13 said:
The QTS will affect the loss in bass response.
mayhem13 said:
A lot of 'ifs', but if the crossover frequency is high enough, it all might just work.
If the speaker cabinets are sufficiently deep and you are removing the back panel only but not the side panels, you probably don't need to change the crossover at all for the frequency above about 200Hz and it will still work very well provided that the "box" is fully stuffed. There would hardly be any changes to the frequency response from about 200Hz up, depending on the baffle width and cabinet depth. You would need to design a new XO between the MTM and the woofer box.
Regards,
Bill
Regards,
Bill
Just what i was thinking about, the Aethers but with a powered bass module and a more dynamic MTM. Say for the sake of arguement that the MTM configuration was for 200hz and up, and the subs used plate amps. The thought was to deliver signal to the sub amps with speaker level inputs and cross the sub using it's onboard filter at 200hz. Then using the sub amp speaker level outs to the MTM section. Could a passive network be designed in between for a 200hz Hipass or is active the only way to go. I'm very fond of the drivers in the sealed box( 2 CA18rly/27TDFC-WGuide loaded) which are reported to have a very flat response on an open baffle. I just feel i'm lacking some spaciousness that the OB might provide. Besides the fact i've got two Dayton RSS315HOs that are dying for a use!
I would say that , depending on the quality of the amplifier active was better, but you could use the high pass in the plate amp in conjunction with a capacitor of suitable size, what about a pair of O-Audio plate amps with the RCA input and RCA output and using a dedicated amp on the mids??
Do you have a separate pre-amp?? or an integrated with a pre-out main - in function??
Is 200 Hz too high for those Daytons??
Do you have a separate pre-amp?? or an integrated with a pre-out main - in function??
Is 200 Hz too high for those Daytons??
Moondog55 said:
The Subs look good till about 800hz with cone breakup setting in, and the low pass filter on the amps is 36db/oct at 200hz. The speaker level in/outs have no high pass...simply a parallel connection so some type of high pass at 200hz would be needed between the amp and MTM section. I could purchase another amp and simple two way active xo, but i'd prefer passive if possible.
mayhem13 said:
Perhaps. I just haven't seen one (meaning a design with measurements). Take, for example the great looking Jamo 909. Their measurements is far from smooth. Compare them to NaO or Phoenix as a reference (unfortunately I have yet to see Orion measurements).
Many use the approach of mounting the drivers off-centre. This may flatten the on-axis response but off-axis would be worse. Again, just my reading/thinking. I havent actually built one and measure such approach.
gainphile said:
I've referenced a few DIY OBs, and many take the approach you mentioned of offset driver alignment. I could easily try multiple alignments on the open baffle as MDF is pretty cheap...and a small price to pay to get it right. I'm fortunate to be a solo listener in my home so i don't have to share the sweet spot with anyone in my dedicated 2ch room.
In the measured freq response of the CA18RLY on an open baffle, i see the rising response of about 6db starting at 1k...is this what you're talking about?
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